There is security software like Avast, Kaspersky, BitDefender and ESET that intercept secure connection certificates and send their own.

https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

https://support.mozilla.org/en-US/kb/firefox-and-other-browsers-cant-load-websites

https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message

https://support.mozilla.org/en-US/kb/connection-untrusted-error-message

Websites don't load - troubleshoot and fix error messages

http://kb.mozillazine.org/Error_loading_websites

What do the security warning codes mean

• MOZILLA_PKIX_ERROR_MITM_DETECTED
• uses an invalid security certificate SSL_ERROR_BAD_CERT_DOMAIN
• configured their website improperly

How to troubleshoot the error code "SEC_ERROR_UNKNOWN_ISSUER" on secure websites https://support.mozilla.org/en-US/kb/troubleshoot-SEC_ERROR_UNKNOWN_ISSUER

Seems to me this is a Firefix/Mozilla problem more than a user problem or one belonging to the sites users visit. I stayed with Firefox right from it's first version till upgrade 56 when a lot of my add-ons no longer worked, but I liked Firefox so much that I tolerated that. But now that FF is interfering with my ability to visit sites I regularly visit and others that I regularly do business with, I'm going to use a different browser that is less troublesome. My security is fine. I've been online for 33 years starting with BBS sites when I was using DOS 3.1 so I'm not a novice at this. Firefox needs to get back to it's basics, providing an open source browser that works for everyone.

I understand how you feel. I am still using v54 myself. I refuse to give up my add-ons.

Does anyone at Firefox and/or Mozilla read these complaints? How about doing something about them? If I'm reading these posts correctly Firefox has to be bleeding users. Time to read the handwriting on the wall and make changes that favor users.

I just did some quick research on browser usage and in May, 2012 Firefox had 24.3% of the market. In May, 2019 that percentage had dropped by nearly 300% to 6.8% of the market. Firefox/Mozilla. Pay attention. People don't like the direction you're moving in.

Hi gruff, for "SSL_ERROR_BAD_CERT_DOMAIN", my question is why the web server -- or an intermediary in your connection -- is sending a non-matching certificate. Something is wrong there.

Are you using your regular home internet connection, or a work connection or public hotspot? Sometimes a request may be replaced in a way that causes a mismatch, so this is my next suggestion:

Try a non-secure address like this:

http://example.com

Do you get an intermediary jumping in to ask for authentication or accepting terms of use? If so, and you do, then you usually can connect securely after that.

The error message I get when I try to visit several of my commonly used websites is posted above in the screenshot I took. It all started when Firefox came out with their update 67.0 and then 67.0.1. It continues, and I notice that several others have had the same thing happen. Either FF or Moz. doesn't care or they don't bother to read these problems as listed. I think it's also notable that since 2012 Firefox usage has dropped by more than 300%. See my post above for the figures on that.

Hi gruff, I read all your replies, so please take another look at mine. You did not answer my question or mention trying my suggestion.

Why would I want to go to a deliberately non-secure address? I'm using my home internet connection via Wecom, Inc. in Kingman, AZ and my machine is hardened. Wecom has been in the business of communications for more than 50 years and I've never had any problems with them. I've also been online for more than 33 years and in all that time have only run into 2 pieces of malware. I keep tight security. This is Mozilla's problem, not mine nor anyone else's.

I did try your "http://example.com" and I received the same yellow boardered message and the extended message noted that the certificate is only valid for pclinkhdmw.clink.motive.com.

I can't belive that you blame Mozilla for the wrong certificate of this page.

It's not connected with your update. Just a coincidence. They have a wrong cert, every sane browser will show you that error.

I'm not the only one blaming Mozilla for problems. In my opinion they started going south with upgrade 56.0 when all my add-ons were discarded and no longer worked. I think my opinion is supported by the fact that Firefox has dropped from 24.3% of the market in 2012 down to 6.8% of the market this year. That's a 300%+ drop in users. I'm a big fan of open source but only if it keeps on working correctly and upgrades do not degrade the browser's performance and functionality.

gruff said

I did try your "http://example.com" and I received the same yellow boardered message and the extended message noted that the certificate is only valid for pclinkhdmw.clink.motive.com.

Hmm, that makes no sense, since it is an HTTP address and by definition you cannot get an HTTPS connection error for an HTTP address -- unless it was redirected. That looks like a potential "affiliate" link, so I suspect your connection may be hijacked.

Connection Setting

You can check that here:

• Windows: "3-bar" menu button (or Tools menu) > Options
• Mac: "3-bar" menu button (or Firefox menu) > Preferences
• Linux: "3-bar" menu button (or Edit menu) > Preferences
• Any system: type or paste about:preferences into the address bar and press Enter/Return to load it

In the search box at the top of the page, type proxy and Firefox should filter to the "Settings" button, which you can click.

The default of "Use system proxy settings" piggybacks on your Windows/IE "LAN" setting. "Auto-detect" can lead to a flaky connection. You may want to try "No proxy".

Any difference?

Hijacker Search and Destruction

Here's my suggested procedure for tracking down and cleaning up bad add-ons and other hijackers. I know it seems long, but it's really not that bad.

(1) Open the Windows Control Panel, Uninstall a Program.

After the list loads, click the "Installed on" column heading to group the infections, I mean, additions, by date. This can help in smoking out undisclosed bundle items that snuck in with some software you agreed to install. Be suspicious of everything you do not recognize/remember, as malware often uses important or innocent sounding names to discourage you from removing it.

Take out as much trash as possible here. If you're not sure, feel free to post program names or a screenshot of the list.

(2) Open Firefox's Add-ons page using either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons
• type or paste about:addons in the address bar and press Enter/Return

In the left column of the Add-ons page, click Extensions.

Then cast a critical eye over the list on the right side. Any extensions Firefox installs for built-in features are hidden from this page, so everything listed here is your choice (and your responsibility) to manage. Anything suspicious or that you just do not remember installing or why? If in doubt, disable (or remove).

Any improvement?

(3) You can search for remaining issues with the scanning/cleaning tools listed in this support article: Troubleshoot Firefox issues caused by malware. These on-demand scanners are free and take considerable time to run. If they finish quickly and especially if they require payment, you may have a serious infection. I suggest the specialized forums listed in the article in that case.

Hopefully that will flush anything on your system and in your Firefox that could be causing this problem.

I did as you asked and the only thing new I found was a Firefox addon that allowed me to save a page in PDF format. I have disabled that and nothing changes.

I think that leaves the possibility that an old extension got "monetized." Could you test in Firefox's Safe Mode? In its Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, any userChrome.css/userContent.css files, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is not running: Hold down the Shift key when starting Firefox. (On Mac, hold down the option/alt key instead of the Shift key.)

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" Help button > Restart with Add-ons Disabled
• (menu bar) Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement?

I can't boot into safe mode. It screws up my desktop (see attached photo) which takes me hours to make right again. I'll just live with it and use FF on those rare occasions when I need to and rely on Chrome and Opera for the majority of my work. I do, however, think that the massive drop in FF users says a lot about Mozilla and how much they care about their users. I wonder what made them lose their morality.

Starting Firefox in Firefox's Safe Mode doesn't involve rebooting your system. I gave you the specific steps in a previous reply.

As for why so many people switched from Firefox to Chrome over the years, I suspect there are a lot of reasons. Each person will make their choice based on their own needs and preferences.

Maybe a 300% reduction in users is because Firefox is becoming a sludge. I'm done. Thanks for trying to help me. Bye.